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BackgroundAngiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin-angiotensin-aldosterone system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic mini-pump. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI).ObjectivesThe authors evaluated effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post-infarction.MethodsC57BL/6 mice underwent permanent left anterior descending coronary artery ligation and cardiac function was assessed using echocardiography for 8 weeks followed by a terminal measurement of left ventricular pressure volume loops. Ang-(1-9) was delivered by adeno-associated viral vector via single tail vein injection immediately following induction of MI. Direct effects of Ang-(1-9) on cardiomyocyte excitation/contraction coupling and cardiac contraction were evaluated in isolated mouse and human cardiomyocytes and in an ex vivo Langendorff-perfused whole-heart model.ResultsGene delivery of Ang-(1-9) reduced sudden cardiac death post-MI. Pressure volume measurements revealed complete restoration of end-systolic pressure, ejection fraction, end-systolic volume, and the end-diastolic pressure volume relationship by Ang-(1-9) treatment. Stroke volume and cardiac output were significantly increased versus sham. Histological analysis revealed only mild effects on cardiac hypertrophy and fibrosis, but a significant increase in scar thickness. Direct assessment of Ang-(1-9) on isolated cardiomyocytes demonstrated a positive inotropic effect via increasing calcium transient amplitude and contractility. Ang-(1-9) increased contraction in the Langendorff model through a protein kinase A–dependent mechanism.ConclusionsOur novel findings showed that Ang-(1-9) gene therapy preserved left ventricular systolic function post-MI, restoring cardiac function. Furthermore, Ang-(1-9) directly affected cardiomyocyte calcium handling through a protein kinase A–dependent mechanism. These data emphasized Ang-(1-9) gene therapy as a potential new strategy in the context of MI.

Summary Obesity is a risk factor for severe complications from coronavirus disease 2019 (COVID‐19). During the COVID‐19 pandemic in Spring 2020, many clinics and obesity centers across Europe were required to close. This study aimed to determine the impact of COVID‐19 on the provision of obesity services across 10 European countries via a survey of physicians (n = 102) specializing in treating persons with obesity (PwO). In total, 62–95 out of 102 physicians reported that COVID‐19 affected obesity‐related services, with cancellations/suspensions ranging from 50% to 100% across the 10 countries. Approximately 75% of cancellations/suspensions were provider‐ rather than patient‐initiated. A median increase of 20%–25% in waiting times was reported for most services across the countries. When services resume, 87 out of 100 physicians consider factors influencing down‐stream patient outcomes as the most relevant factors for prioritizing interventional treatment. Responses showed that 65 out of 102 and 36 out of 102 physicians believed it (highly) likely that a change in treatment guidance will occur to prioritize earlier interventional treatment for the management of PwO, by either using bariatric surgery or pharmacotherapy, respectively. Results from this study provide important learnings, such as opportunities for, and discrepancies in, the provision of alternative care in light of services cancellations or delays, which may be important for the future management of obesity, especially during future waves of COVID‐19 or other infectious pandemics.

In the isolated rat carotid artery, the endocannabinoid anandamide induces endothelium-dependent relaxation via activation of the enzyme sphingosine kinase (SK). This generates sphingosine-1-phosphate (S1P) which can be released from the cell and activates S1P receptors on the endothelium. In anaesthetised mice, anandamide has a well-characterised triphasic effect on blood pressure but the contribution of SK and S1P receptors in mediating changes in blood pressure has never been studied. Therefore, we assessed this in the current study.The peak hypotensive response to 1 and 10 mg/kg anandamide was measured in control C57BL/6 mice and in mice pretreated with selective inhibitors of SK1 (BML-258, also known as SK1-I) or SK2 ((R)-FTY720 methylether (ROMe), a dual SK1/2 inhibitor (SKi) or an S1P1 receptor antagonist (W146). Vasodilator responses to S1P were also studied in isolated mouse aortic rings.The hypotensive response to anandamide was significantly attenuated by BML-258 but not by ROMe. Antagonising S1P1 receptors with W146 completely blocked the fall in systolic but not diastolic blood pressure in response to anandamide. S1P induced vasodilation in denuded aortic rings was blocked by W146 but caused no vasodilation in endothelium-intact rings.This study provides evidence that the SK1/S1P regulatory-axis is necessary for the rapid hypotension induced by anandamide. Generation of S1P in response to anandamide likely activates S1P1 to reduce total peripheral resistance and lower mean arterial pressure. These findings have important implications in our understanding of the hypotensive and cardiovascular actions of cannabinoids.

Aims Identifying novel mediators of lethal myocardial reperfusion injury that can be targeted during primary percutaneous coronary intervention (PPCI) is key to limiting the progression of patients with ST-elevated myocardial infarction (STEMI) to heart failure. Here we show through parallel clinical and integrative preclinical studies the significance of the protease cathepsin-L on cardiac function during reperfusion injury. Methods and Results We found that direct cardiac release of cathepsin-L in STEMI patients (n = 76) immediately post-PPCI leads to elevated serum cathepsin-L levels and that serum levels of cathepsin-L in the first 24 hour post-reperfusion are associated with reduced cardiac contractile function and increased infarct size. Preclinical studies, demonstrate that inhibition of cathepsin-L release following reperfusion injury with CAA0225 reduces infarct size and improves cardiac contractile function by limiting abnormal cardiomyocyte calcium handling and apoptosis. Conclusion Our findings suggest that cathepsin-L is a novel therapeutic target that could be exploited clinically to counteract the deleterious effects of acute reperfusion injury after an acute STEMI. Translational perspective New therapeutic targets are urgently required to limit myocardial damage after reperfusion injury. We identified cardiac release of the protease cathepsin-L among patients following primary percutaneous coronary intervention (PPCI). Elevated serum levels of cathepsin-L were associated with reduced contractile function and increased infarct size at 24 hour and 6 months post-PPCI. Work conducted using animal models indicated that cardiac release of cathepsin-L mediated cardiac dysfunction following reperfusion injury. Specific inhibition of cathepsin-L prevented abnormal calcium handling, reduced infarct size and improved contractile function. These novel findings offer the prospect of targeting cathepsin-L-mediated cardiac dysfunction after PPCI.

BackgroundPost-MI various cellular and extracellular matrix changes occur in the infarct, border zone (BZ) and left ventricular (LV) regions of the heart due to death of cardiomyocytes. In a significant proportion of patients with MI, these changes can lead to adverse cardiac remodelling with subsequent reduced myocardial function resulting in heart failure (HF). The transcription factor Runx1, required for the differentiation of haematopoetic stem cells and normally absent in adult cardiomyoyctes, is switched on in BZ cardiomyocytes. Our objective is to answer the question – is Runx1 merely a marker of cardiomyocyte damage or does it play a significant functional role post-MI?ResultsRunx1 is expressed within the BZ and remote LV myocardium in a mouse model of MI and its expression negatively correlates with cardiac function measured by pressure-volume (PV) loop analysis. A tamoxifen inducible, cardiomyocyte specific Runx1 deficient mouse has preserved LV systolic function, lack of LV wall thinning and reduced LV dilation post-MI measured by echocardiography and PV loop analysis. Runx1 deficient mice have maintained LV free wall thickness with no change in infarct size or fibrosis 8 wk post-MI. Runx1 deficient mice are protected against eccentric hypertrophy. Functionally, Runx1 deficient mice have larger Ca2+ transients, increased SR Ca2+ content, and increased SERCA function with improved contractility 2 wk post-MI. Runx1 deficient mice show reduced PP1 and levels greater PLB phosphorylationConclusionRunx1 is a new target with therapeutic potential to improve cardiomyocyte Ca2+ handling and contractility post-MI thereby preventing adverse cardiac remodelling and progression to heart failure.

Ischaemia-reperfusion (IR) injury contributes to the cardiac damage following myocardial infarction and paradoxically reduces the benefits of reperfusion therapy. In patients with ischaemic heart disease, cathepsin-L is elevated in the serum and correlates with disease severity. Our data demonstrate that cathepsin-L released from ex vivo rat hearts after ischaemia, and the cathepsin-L inhibitor CAA0225 improves cardiac function during ischaemia-reperfusion ex vivo. However, the effects of the CAA0225 in in vivo hearts during ischaemia-reperfusion are unknown. We hypothesised that using CAA0225 in an in vivo mouse model of ischaemia-reperfusion would identify the role cathepsin-L plays during ischaemia-reperfusion. Ischaemia-reperfusion injury was induced by 45 min temporary coronary artery ligation and CAA0225 was given by intra-venous injection during ischaemia before reperfusion. Double-dye staining demonstrated no difference in area at risk between groups whereas CAA0225 significantly reduced infarct size to 73% of control. Echocardiography demonstrated significantly preserved left ventricular fractional shortening at 2 wk and 4 wk post-IR in CAA0225 treated mice compared with control mice. PV loop measurements demonstrated CAA0225 treated mice had higher developed pressure than control mice at 2 weeks post-IR. Ex vivo isolated rat cardiomyocytes demonstrated that ischemia-reperfusion increased calcium influx through L-type calcium channels, reduced sarcolemmal NCX extrusion and SERCA activity. While CAA0225 treatment normalised the abnormalities of intracellular calcium handling parameters back to control thus reducing calcium waves following ischaemia-reperfusion. These data demonstrate for the first time that CAA0225 protects against ischaemia-reperfusion injury in mice and the mechanism relates to the normalisation of abnormal calcium handling following ischaemia-reperfusion injury.

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